Among conventional circuit board assemblies of this type, some are known to prevent electronic components and a conductive line on a component mounting board from coming into contact with a shield case so as not to bring about a short-circuited state. Japanese Unexamined Patent Publication No. 2005-99506 discloses an assembly with a holding member of insulating material to hold the component mounting board in suspension inside a shield case. Japanese Unexamined Utility Model Publication No. 02-120783 discloses another assembly with a plurality of pedestals in a shield case to hold a component mounting board in suspension.